Packaging adhesive film, manufacturing method for photovoltaic module, and solar photovoltaic module

Abstract

A packaging adhesive film, a manufacturing method for a photovoltaic module, and a solar photovoltaic module. The packaging adhesive film comprises an adhesive film body (4). The adhesive film body (4) comprises a middle film layer (41) and end film layers (42) at least provided at the two opposite ends of the middle film layer (41), the thickness of the end film layers (42) being greater than the thickness of the middle film layer (41). The two opposite side surfaces of the middle film layer (41) are each provided with a first protruding structure (1); the two opposite side faces of each end film layer (42) are each provided with a second protruding structure (2); and the top ends of the first protruding structure (1) and the second protruding structure (2) on the same side are both located on the same plane, said plane being parallel to the adhesive film body (4).

Description

Encapsulation film, photovoltaic module manufacturing method, and solar photovoltaic module

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 14, 2023, with application number 202311019776.3, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of photovoltaic power generation technology, for example, to an encapsulation film, a method for manufacturing a photovoltaic module, and a solar photovoltaic module. Background Art

[0003] With the continuous advancement of solar cells, the development of photovoltaic modules is accelerating. In related art, as shown in Figure 1, a photovoltaic module consists of a glass cover plate 1′, an adhesive film 2′, and a cell 3′. The adhesive film 2′ is a thermosetting, viscous resin film that encapsulates and protects the cell 3′. During the production of a photovoltaic module, two adhesive films 2′ are stacked on either side of the cell 3′, and then two glass cover plates 1′ are stacked on top of the adhesive films 2′. Finally, the photovoltaic module is hot-pressed. The two adhesive films 2′ melt and cross-link, filling the gap between the two glass cover plates 1′. Simultaneously, the glass cover plates 1′ and the adhesive films 2′, as well as the cell 3′ and the adhesive films 2′, are bonded and fixed. After the adhesive film 2′ cures, the glass cover plate 1′, the adhesive film 2′, and the cell 3′ are laminated together to form the photovoltaic module. To ensure sufficient adhesive at the edges of the laminated photovoltaic module, the adhesive films 2′ are typically thin in the middle and thick at the ends.

[0004] The photovoltaic modules of the related art have the following drawbacks: during transportation and storage of the films 2', multiple sheets of film 2' must be stacked and rolled together. The thinner-in-the-middle-and-thicker-at-the-ends structure of the films 2' prevents them from being rolled up smoothly, allowing air to enter the gaps between adjacent sheets and causing deterioration of the film 2' material.

[0005] Summary of the Invention

[0006] The present application provides a packaging film, which has a flat surface when stacked and rolled up, thereby preventing air from entering the gap between two adjacent packaging films and causing material deterioration.

[0007] The present application provides a method for manufacturing a photovoltaic module, which can use the end film layer of the packaging film to fill the gap between two cover plates to improve the sealing performance.

[0008] The present application provides a solar photovoltaic assembly with good sealing performance.

[0009] An embodiment of the present application provides an encapsulation film, including a film body, wherein the film body includes a middle film layer and at least end film layers arranged at opposite ends of the middle film layer, and the thickness of the end film layers is greater than the thickness of the middle film layer; along the thickness direction of the film body, the opposite side surfaces of the middle film layer are each provided with a first protrusion structure, and the opposite side surfaces of the end film layers are each provided with a second protrusion structure, the top of the first protrusion structure and the top of the second protrusion structure located on the same side are both located on the same plane, and the plane where the top of the first protrusion structure and the top of the second protrusion structure located on the same side are located is parallel to the film body.

[0010] In one embodiment, along the thickness direction of the adhesive film body, two opposite side surfaces of the middle film layer are respectively a first side surface and a second side surface, and the end film layer protrudes from at least one of the first side surface and the second side surface.

[0011] In one embodiment, when the end film layer protrudes from the first side surface and the second side surface, the second protruding structures located on both sides of the end film layer have the same height.

[0012] In one embodiment, the adhesive film body also includes a transition film layer, the two ends of the transition film layer are respectively connected to the middle film layer and the end film layer, and a third protruding structure is provided on the side of the transition film layer. The top of the third protruding structure and the top of the first protruding structure are located on the same plane, and the first protruding structure, the second protruding structure and the third protruding structure are integrally pressed and formed.

[0013] In one embodiment, the first protruding structure, the second protruding structure, and the third protruding structure each include a plurality of protruding ridges interwoven into a mesh, and the cross-section of the protruding ridges is triangular.

[0014] In one embodiment, the thickness of the transition film layer gradually increases from an end close to the middle film layer to an end close to the end film layer.

[0015] In one embodiment, the thickness of the end film layer gradually increases from an end close to the middle film layer to an end away from the middle film layer.

[0016] In one embodiment, the end film layers are disposed around the middle film layer.

[0017] An embodiment of the present application also provides a method for manufacturing a photovoltaic module, providing a cover plate, a battery cell and an encapsulation film, wherein there are two cover plates and two encapsulation films. The method for manufacturing a photovoltaic module includes: stacking the cover plate, the battery cell and the encapsulation film together from bottom to top in the order of the cover plate, the encapsulation film, the battery cell, the encapsulation film and the cover plate; heating the encapsulation film, and driving the two cover plates close together to squeeze the encapsulation film so that the melted encapsulation film is wrapped around the outer surface of the battery cell.

[0018] An embodiment of the present application also provides a solar photovoltaic module, which is processed by the above-mentioned photovoltaic module manufacturing method, including a cover plate, an adhesive layer and a battery cell, the adhesive layer is wrapped around the outer surface of the battery cell, there are two cover plates, the two cover plates are arranged on two opposite sides of the adhesive layer, and the cover plates are parallel to the battery cell, and the two encapsulation adhesive films are laminated and fused together to form the adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram of a solar photovoltaic module before lamination in the related art.

[0020] FIG2 is a cross-sectional view of the packaging film according to the first embodiment of the present application.

[0021] FIG3 is a partial cross-sectional view of the packaging film according to the first embodiment of the present application.

[0022] FIG4 is a front view of the packaging film according to the first embodiment of the present application.

[0023] FIG5 is a cross-sectional view of the packaging film according to the second embodiment of the present application.

[0024] FIG6 is a cross-sectional view of the packaging film according to the third embodiment of the present application.

[0025] FIG7 is a schematic diagram of a solar photovoltaic module before lamination according to the fourth embodiment of the present application.

[0026] FIG8 is a schematic diagram of the solar photovoltaic assembly after lamination according to the fourth embodiment of the present application.

[0027] In Figure 1:

[0028] 1′, glass cover; 2′, adhesive film; 3′, battery cell.

[0029] In Figures 2 to 8:

[0030] 1. First raised structure; 11. Raised ridges; 2. Second raised structure; 3. Third raised structure; 4. Adhesive film body; 41. Middle film layer; 411. First side surface; 412. Second side surface; 42. End film layer; 43. Transition film layer; 5. Cover plate; 6. Battery cell; 7. Adhesive layer; 8. Edge cavity. DETAILED DESCRIPTION

[0031] The technical solution of this application is explained below with reference to the accompanying drawings and through specific implementation methods.

[0032] Example 1

[0033] As shown in Figures 2, 3 and 7, the present application provides an encapsulation film, which is applied to a solar photovoltaic module. The solar photovoltaic module includes two cover plates 5, two encapsulation films and a battery cell 6. The encapsulation film plays a role in encapsulating and protecting the battery cell 6. The encapsulation film is stacked on the two side surfaces of the battery cell 6 in the thickness direction. The area of ​​the encapsulation film is larger than the area of ​​the battery cell 6, and the periphery of the encapsulation film extends to the outside of the battery cell 6. An edge cavity 8 is formed between the two encapsulation films and the battery cell 6. The two cover plates 5 are respectively stacked on the side of the two encapsulation films facing away from the battery cell 6. Finally, the cover plates 5, the encapsulation films and the battery cell 6 are hot pressed, and the melted encapsulation film is filled into the edge cavity 8 and bonded to the cover plate 5 and the battery cell 6 to achieve encapsulation of the battery cell 6.

[0034] The encapsulating film includes a film body 4, which includes a middle film layer 41 and an end film layer 42. The middle film layer 41 is located in the middle area of ​​the film body 4, and the end film layers 42 are located at opposite ends of the film body 4. The thickness of the middle film layer 41 is H1, and the thickness of the end film layer 42 is H2, and H2>H1. Along the thickness direction of the film body 4 (Z direction in the figure), the two opposite sides of the middle film layer 41 are respectively a first side 411 and a second side 412. The first side 411 and the second side 412 are both provided with a first protruding structure 1. The first protruding structure 1 is an embossed structure formed on the middle film layer 41 by rolling, and the embossed structure is in a grid or pattern shape. The first protruding structure 1 can cover the entire corresponding first side 411 or the corresponding second side 412. The function of the first protruding structure 1 is to increase the friction coefficient of the surface of the middle film layer 41 to promote the fitting and assembly of the encapsulating film with other components.

[0035] Second protrusions 2 are provided on opposite sides of the end film layer 42. The shape and function of the second protrusions 2 are identical to those of the first protrusions 1 and will not be further described here. The tops of the first and second protrusions 1 and 2 on the same side of the encapsulating film lie on the same plane, and the plane of the tops of the first and second protrusions 1 and 2 on the same side of the encapsulating film is parallel to the film body 4. This structure flattens both sides of the encapsulating film through its thickness, facilitating stacking multiple films for storage and transport, and ensuring that the encapsulating film remains flat when attached to the surface of another component.

[0036] Optionally, end film layers 42 are disposed around the middle film layer 41. Exemplarily, the middle film layer 41 is rectangular or square, with end film layers 42 disposed at both ends of the middle film layer 41 in the first direction, and end film layers 42 disposed at both ends of the middle film layer 41 in the second direction. All end film layers 42 are integrally structured, surrounding the middle film layer 41. The first direction is perpendicular to the second direction.

[0037] Optionally, along the thickness direction of the film body 4, the two opposite side surfaces of the end film layer 42 protrude from the first side surface 411 and the second side surface 412 of the middle film layer 41, respectively. Of the two opposite side surfaces of the end film layer 42, the height by which the side corresponding to the first side surface 411 protrudes from the first side surface 411 and the height by which the side corresponding to the second side surface 412 protrudes from the second side surface 412 are the same. This can also be understood as the symmetrical arrangement of the two side surfaces in the thickness direction of the film body 4 for ease of manufacturing and processing. The height of the second protruding structures 2 located on both side surfaces of the end film layer 42 is the same. The height of the first protruding structure 1 located on the middle film layer 41 is H3, and the height of the second protruding structure 2 located on the end film layer 42 is H4. In order to make the two side surfaces of the encapsulation film flat in the thickness direction, H1+2H3=H2+2H4 must be satisfied.

[0038] Optionally, the film body 4 further includes a transition film layer 43, the ends of which are connected to the middle film layer 41 and the end film layers 42, respectively. The transition film layer 43 serves to smoothly transition the thickness of the film body 4 from H1 to H2. Specifically, the thickness of the transition film layer 43 gradually increases from the end closest to the middle film layer 41 to the end closest to the end film layer 42. The provision of the transition film layer 43 facilitates a more uniform thickness of the encapsulating film after lamination.

[0039] The transition film layer 43 is provided with third protrusions 3 on opposite sides. The shape and function of the third protrusions 3 are identical to those of the first protrusions 1 and are not further described here. The tops of the first, second, and third protrusions 1, 2, and 3 on the same side of the film body 4 are all located on the same plane.

[0040] Optionally, as shown in Figures 3 and 4 , the middle film layer 41, the transition film layer 43, and the end film layer 42 are integrally formed. The first raised structure 1, the second raised structure 2, and the third raised structure 3 are integrally formed by press molding. The first raised structure 1, the second raised structure 2, and the third raised structure 3 are collectively referred to as the raised structures. The raised structures are made of the same material as the film body 4. In practical applications, the raised structures can be formed by rolling onto the film body 4 using an embossing die.

[0041] The first, second, and third raised structures 1, 2, and 3 each include a plurality of ridges 11 interwoven into a mesh. Alternatively, the film body 4 may be understood as having multiple ridges 11 spaced apart along a first direction and multiple ridges 11 spaced apart along a second direction, with the first and second directions forming an angle. Both ends of the ridges 11 extend to the edges of the film body 4. The cross-section of the ridges 11 is triangular, with one side of the triangle corresponding to the side of the ridge 11 connected to the film body 4. The corner of the triangle facing away from the film body 4 forms the apex of the raised structure.

[0042] The purpose of the raised structure is to create an uneven surface on both sides of the encapsulating film, thereby increasing the film's coefficient of friction. Therefore, the cross-section of the raised ridges 11 is not limited to a triangle; other shapes such as a trapezoid, a semicircle, or a rectangle are also possible. Furthermore, the raised structure is not limited to a mesh-like structure; other shapes such as irregular patterns or concentric ring patterns are also possible.

[0043] By providing a raised structure on the film body 4, the raised structure is utilized to increase the friction coefficient of the surface of the packaging film. When the packaging film is fitted to the cover plate 5, it is beneficial to increase the friction between the packaging film and the cover plate 5, and prevent the packaging film and the cover plate 5 from shifting in position. During the storage and transportation of the packaging film, multiple packaging films are stacked together. By providing a raised structure, adhesion between two adjacent packaging films can also be prevented, so that the packaging films can be separated during use. By providing the tops of all the raised structures on the same plane, the two side surfaces of the packaging film are flat, and when the packaging film is stacked and rolled, the two adjacent packaging films can be tightly fitted together, preventing air from entering the gap between adjacent packaging films and causing material deterioration. By making the thickness of the end film layer 42 greater than the thickness of the middle film layer 41, the gram weight of the edge area of ​​the packaging film is relatively large. During lamination, a portion of the end film layer 42 melts and fills the edge cavity 8, allowing the two cover plates 5 to remain parallel after lamination, with sufficient encapsulation film between the two cover plates 5 to wrap the solar cells 6. This structure ensures a more sufficient amount of adhesive at the edge of the solar photovoltaic module, improving the sealing of the solar photovoltaic module.

[0044] Example 2

[0045] As shown in FIG5 , a packaging film is provided, the structure of which is similar to that of Example 1. Along the thickness direction of the film body 4 , one side surface of the end film layer 42 protrudes from the first side surface 411 of the middle film layer 41 , and the other side surface is flush with the second side surface 412 of the middle film layer 41 . This structure enables the end film layer 42 to have a greater gram weight than the middle film layer 41 , thereby avoiding the problem of insufficient adhesive at the edge of the solar photovoltaic module due to overflow of the packaging film during lamination. Of course, in other embodiments, one side surface of the end film layer 42 can also be set to protrude from the second side surface 412 of the middle film layer 41 , and the other side surface is flush with the first side surface 411 .

[0046] The second raised structures 2 on the two side surfaces of the end film layer 42 have different heights. The height of the second raised structures 2 located on the side of the end film layer 42 corresponding to the second side 412 is equal to the height of the first raised structures 1. The height of the second raised structures 2 located on the side of the end film layer 42 corresponding to the first side 411 is less than the height of the first raised structures 1. In practice, the height of the second raised structures 2 matches the height of the end film layer 42 protruding from the first side 411, ensuring that the tops of the first and second raised structures 1 and 2 on the same side of the film body 4 are coplanar. Similarly, the height of the third raised structures 3 matches the height of the transition film layer 43 protruding from the first side 411, ensuring that the tops of all raised structures on the same side of the film body 4 are coplanar.

[0047] Example 3

[0048] As shown in Figure 6, a packaging film is provided, and its structure is similar to that of Example 1. The thickness of the end film layer 42 gradually increases from the end close to the middle film layer 41 to the end away from the middle film layer 41. It can also be understood that the two side surfaces of the end film layer 42 in the thickness direction are inclined relative to the side surfaces of the middle film layer 41. By setting the side surfaces of the end film layer 42 at an angle, while increasing the gram weight of the end film layer 42, the thickness variation of the end film layer 42 can also be made more uniform, so that the thickness of the packaging film after lamination is more uniform. Since the thickness variation of the end film layer 42 is relatively uniform and gentle, it also has the function of the transition film layer 43. Therefore, in this embodiment, the transition film layer 43 is eliminated in the packaging film.

[0049] Because the thickness of the end film layer 42 continuously changes, the height of the second protruding structure 2 provided on the end film layer 42 also continuously changes. In practice, the height of the second protruding structure 2 matches the height of the end film layer 42 protruding from the first side surface 411, ensuring that the top of the first protruding structure 1 and the top of the second protruding structure 2 on the same side of the film body 4 are located in the same plane.

[0050] Example 4

[0051] As shown in Figures 7 and 8, the present application also provides a method for manufacturing a photovoltaic module for manufacturing a solar photovoltaic module. The cover plate 5 and the packaging film are both two, and the method includes the following steps:

[0052] Step S1: Stack the cover plate 5, the battery cell 6, and the encapsulation film together from bottom to top in the order of cover plate 5, encapsulation film, battery cell 6, encapsulation film, and cover plate 5. The two encapsulation films are respectively stacked on the two side surfaces in the thickness direction of the battery cell 6, and the encapsulation films are able to completely cover the battery cell 6. The edge of the battery cell 6 extends to the corresponding area of ​​the end film layer 42, and the periphery of the encapsulation film extends to the outside of the battery cell 6, so that the two encapsulation films and the battery cell 6 enclose an edge cavity 8. The two cover plates 5 are respectively stacked on the side of the two encapsulation films facing away from the battery cell 6, and the edge of the cover plate 5 is aligned with the edge of the encapsulation film.

[0053] Step S2: Heat the encapsulation film to melt it. Drive the two cover plates 5 toward each other so that the two cover plates 5 squeeze the encapsulation film. The melted encapsulation film is bonded to the cover plates 5 and the cell 6. At the same time, a portion of the end film layer 42 is filled into the edge cavity 8 so that the encapsulation film wraps around the outer surface of the cell 6. Finally, the two cured encapsulation films form a whole, encapsulating the cell 6. The cover plates 5, encapsulation film, and cell 6 are laminated together to form a solar photovoltaic module.

[0054] It should be noted that after the packaging film is laminated, the first protruding structure 1 , the second protruding structure 2 and the third protruding structure 3 are all integrated with the film body 4 .

[0055] In this embodiment, since the gram weight of the corresponding area of ​​the end film layer 42 of the encapsulation film is greater than the gram weight of the corresponding area of ​​the middle film layer 41, during lamination, the end film layer 42 can provide sufficient glue to fill the edge cavity 8, thereby ensuring the sealing performance of the entire solar photovoltaic module.

[0056] Example 5

[0057] As shown in Figure 8, the present application also provides a solar photovoltaic module, including a cover plate 5, an adhesive layer 7 and a battery cell 6. The adhesive layer 7 is formed by fusing two encapsulating adhesive films by hot pressing. The adhesive layer 7 is wrapped around the outer surface of the battery cell 6. The cover plate 5 is a glass cover plate, and there are two cover plates 5. Along the thickness direction of the battery cell 6, the two cover plates 5 are arranged on two opposite sides of the adhesive layer 7, and the cover plates 5 are parallel to the battery cell 6. The adhesive layer 7 is bonded and fixed to the cover plate 5 and the battery cell 6. Both the cover plate 5 and the adhesive layer 7 are light-transmitting, so that sunlight can pass through the cover plate 5 and the adhesive layer 7 and irradiate the battery cell 6. The battery cell 6 is configured to perform photoelectric conversion to generate electrical energy.

[0058] In this embodiment, since the gram weight of the corresponding area of ​​the end film layer 42 of the encapsulation film is greater than the gram weight of the corresponding area of ​​the middle film layer 41, during lamination, the end film layer 42 can provide sufficient glue to fill the edge cavity 8, thereby ensuring the sealing performance of the entire solar photovoltaic module.

[0059] The above contents are merely optional embodiments of the present application. For ordinary technicians in this field, according to the concept of the present application, there may be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present application.

Claims

1. A packaging film, comprising a film body, wherein the film body comprises a middle film layer and end film layers at least arranged at two opposite ends of the middle film layer, wherein the thickness of the end film layers is greater than the thickness of the middle film layer; Along the thickness direction of the adhesive film body, the two opposite side surfaces of the middle film layer are provided with a first protrusion structure, and the two opposite side surfaces of the end film layer are provided with a second protrusion structure, and the top of the first protrusion structure and the top of the second protrusion structure located on the same side are located on the same plane, and the plane where the top of the first protrusion structure and the top of the second protrusion structure located on the same side are located is parallel to the adhesive film body.

2. The packaging film according to claim 1, wherein: Along the thickness direction of the adhesive film body, two opposite side surfaces of the middle film layer are respectively a first side surface and a second side surface, and the end film layer protrudes from at least one of the first side surface and the second side surface.

3. The packaging film according to claim 2, wherein: In a case where the end film layer protrudes from the first side surface and the second side surface, the second protruding structures located on both sides of the end film layer have the same height.

4. The packaging film according to any one of claims 1 to 3, wherein: The adhesive film body also includes a transition film layer, the two ends of which are respectively connected to the middle film layer and the end film layer, a third protrusion structure is arranged on the side of the transition film layer, the top of the third protrusion structure and the top of the first protrusion structure are located on the same plane, and the first protrusion structure, the second protrusion structure and the third protrusion structure are integrally pressed and formed.

5. The packaging film according to claim 4, wherein: The first protrusion structure, the second protrusion structure and the third protrusion structure each include a plurality of protrusions interwoven into a mesh, and the cross section of the protrusions is triangular.

6. The packaging film according to claim 4, wherein: The thickness of the transition film layer gradually increases from one end close to the middle film layer to one end close to the end film layer.

7. The packaging adhesive film according to any one of claims 1 to 3, wherein: The thickness of the end film layer gradually increases from an end close to the middle film layer to an end away from the middle film layer.

8. The packaging adhesive film according to any one of claims 1 to 3, wherein: The end film layers are arranged around the middle film layer.

9. A method for manufacturing a photovoltaic module, comprising providing a cover plate, a battery cell and a packaging film according to any one of claims 1 to 8, wherein there are two of each of the cover plate and the packaging film, and the method for manufacturing a photovoltaic module comprises: Stacking the cover plate, the battery cell and the packaging film together from bottom to top in the order of the cover plate, the packaging film, the battery cell, the packaging film and the cover plate; The packaging film is heated, and the two cover plates are driven to approach each other to squeeze the packaging film, so that the melted packaging film is wrapped around the outer surface of the battery cell.

10. A solar photovoltaic module, processed by the photovoltaic module manufacturing method according to claim 9, comprising a cover plate, an adhesive layer and a battery cell, wherein the adhesive layer is wrapped around the outer surface of the battery cell, there are two cover plates, the two cover plates are arranged on two opposite sides of the adhesive layer, and the cover plates are parallel to the battery cell, and two packaging adhesive films are laminated and fused together to form the adhesive layer.

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